Is there a problem with the notification emails?

A few days ago I did not receive the e-mail notification of the emails.

Do you know why?

Thank you

I have checked your email address and did not find it in our bounce list, one of the reasons why emails do not send from our servers, and when checking the email history I could see there were indeed failed emails, but the last test was successfully sent.

You could also see the email history here: How-to-View-All-Your-Form-Email-History

Here is also a screenshot of a test that I made where it is shown successfully: 

If the problem still persists I would suggest you to check this guide: https://www.jotform.com/help/364-Why-I-am-not-Receiving-Email-Notifications 

Also, you could try setting up your custom sender email address using the SMTP feature that will allow you to have more control over the sender info, here's the guide that will help you with that: https://www.jotform.com/help/244-How-to-Setup-SMTP-for-a-Form 

Hope this helps.